Despite a down economy, four museums in Ohio are embarking on big expansion projects. The Cleveland Museum of Art announced plans two months ago for a $225 million renovation and expansion, the Toledo Museum of Art is spending $27 million on a new, 47,000-square-foot center for glass art, in June, the Contemporary Arts Center in Cincinnati will open its new $37-million Lois and Richard Rosenthal Center, designed by Zaha Hadid of London, and the Akron Museum is raising $34 million for an expandion.